The final remaining Democratic presidential candidates, former Secretary of State Hillary Clinton and Vermont Sen. Bernie Sanders, revved up for Sunday's CNN debate following a spate of first-round voting contests over the weekend and on Super Tuesday last week. The Democratic hopefuls were set to meet in Flint, Michigan, to discuss the city's water crisis, as well as their proposed economic and foreign policy plans.

The debate came just one day after caucus wins for Sanders in Kansas and Nebraska and a primary victory for Clinton in Louisiana. The pair will also compete Tuesday for primary votes in the state of Michigan, where Clinton is slated to win with a wide margin, according to polls of likely Democratic voters from RealClearPolitics, which takes the average of recent polling information. From economics to foreign policy, here are four things to watch for in tonight’s Democratic debate.

The water crisis in the city of Flint is slated to serve as a debate topic for the candidates, both of whom have made statements condemning the citywide scandal after a cost-cutting move by the local government caused dangerous levels of lead in thousands of people's water supply. The water was contaminated after Flint authorities changed the city’s source from Detroit to the Flint River without adding anti-corrosive elements to the water, causing lead to leach into the water. While the local government has switched the water source back to Detroit water, the controversy has sparked discussion among the candidates concerning the ways in which minority communities are disproportionately affected by environmental hazards.

“I spent a lot of time last week being outraged by what's happening in Flint, Michigan, and I think every single American should be outraged,” Clinton said at an MSNBC debate in February when asked to identify an issue that had not been covered in that night’s discussion. “We've had a city in the United States of America where the population, which is poor in many ways and majority African-American, has been drinking and bathing in lead-contaminated water,” she said. “And the governor of that state acted as though he didn't really care.”

Sanders is expected to bring up Clinton’s history of giving lucrative speeches to Wall Street companies, where she reportedly earned hundreds of thousands of dollars in speaking fees. The Vermont senator has urged her to release the transcripts of those speeches, while saying that someone who had been paid so much by Wall Street would not be able to show objectivity in office.

The Food Bank of Eastern Michigan holds stacks of bottled water in the agency’s warehouse to be distributed to the public, after elevated lead levels were found in water in Flint, Michigan, Dec. 16, 2015.Photo: Reuters/Rebecca Cook

Both candidates have gone head-to-head on trade and economic plans for the country, and each Democratic hopeful has tried to present their plan as the best option for a shrinking middle class. Sanders has accused Clinton of being too concerned with corporate interests, frequently referring to her close ties with Wall Street.

Clinton, meanwhile, has advocated for free trade and promised to boost the middle class, accusing Sanders’ socialist plans of being idealistic and impossible to execute. "Anyone running for president owes it to you to come up with real ideas. ... A credible strategy designed for the world we live in now," Clinton said Friday in Detroit, the Associated Press reported.

The militant organization known as the Islamic State group claimed responsibility for a suicide bombing in Hillah, Iraq, Sunday that left at least 60 people dead and dozens more wounded. The recent attack may serve as a point of entrance to discuss the two candidates’ plans for foreign policy in the Middle East. Clinton has frequently performed better on foreign policy issues in debates, given her experience as secretary of state. Sanders will need to convince U.S. voters that he could keep them safe from the mounting threats of Islamic extremism.